This invention relates to a combined gear change and brake control unit for a bicycle. More precisely, this invention relates to a combined unit of the type described by the Applicant in document EP 0 504 118. This document describes a combined control unit comprising a support body connected to a brake control lever pivoting around a first axis and a gear change control unit connected to the support body. The gear change control unit comprises a shaft turnable around a second axis orthogonal to said first axis and carrying a pulley on which the end portion of a control cable of a front or rear derailleur of a bicycle is wound. The rotation of the shaft in a first direction can be controlled by means of a gear change lever, which is arranged immediately behind the brake control lever, while the rotation of the shaft in a second direction can be controlled by means of a button lever, operating on a gear, which is solidly fastened to the shaft. As concerns the shaft control in said second direction, the control unit of the known kind consists of a spring retainer mechanism to withhold the shaft in a number of reference positions. The button lever is destined to co-operate with the gear solidly fastened to the shaft by means of a meshing unit, to produce the rotation of the shaft from one of said reference positions to another.
The objective of this invention is to provide a gear change control unit which is constructively more simple and cost-effective than the one described above. An additional objective of this invention is to provide a gear change control unit requiring a very limited stroke of the button lever to shift the gear.
According to this invention, these objectives are attained by means of a combined control unit which characteristics are described in the main claim.